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Castán-Guerrero C, Krizmancic D, Bonanni V, Edla R, Deluisa A, Salvador F, Rossi G, Panaccione G, Torelli P. A reaction cell for ambient pressure soft x-ray absorption spectroscopy. Rev Sci Instrum 2018; 89:054101. [PMID: 29864817 DOI: 10.1063/1.5019333] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/07/2023]
Abstract
We present a new experimental setup for performing X-ray Absorption Spectroscopy (XAS) in the soft X-ray range at ambient pressure. The ambient pressure XAS setup is fully compatible with the ultra high vacuum environment of a synchrotron radiation spectroscopy beamline end station by means of ultrathin Si3N4 membranes acting as windows for the X-ray beam and seal of the atmospheric sample environment. The XAS detection is performed in total electron yield (TEY) mode by probing the drain current from the sample with a picoammeter. The high signal/noise ratio achievable in the TEY mode, combined with a continuous scanning of the X-ray energies, makes it possible recording XAS spectra in a few seconds. The first results show the performance of this setup to record fast XAS spectra from sample surfaces exposed at atmospheric pressure, even in the case of highly insulating samples. The use of a permanent magnet inside the reaction cell enables the measurement of X-ray magnetic circular dichroism at ambient pressure.
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Affiliation(s)
- C Castán-Guerrero
- Laboratorio TASC, IOM-CNR, S.S. 14 km 163.5, Basovizza 34149, Trieste, Italy
| | - D Krizmancic
- Laboratorio TASC, IOM-CNR, S.S. 14 km 163.5, Basovizza 34149, Trieste, Italy
| | - V Bonanni
- Laboratorio TASC, IOM-CNR, S.S. 14 km 163.5, Basovizza 34149, Trieste, Italy
| | - R Edla
- Laboratorio TASC, IOM-CNR, S.S. 14 km 163.5, Basovizza 34149, Trieste, Italy
| | - A Deluisa
- Laboratorio TASC, IOM-CNR, S.S. 14 km 163.5, Basovizza 34149, Trieste, Italy
| | - F Salvador
- Laboratorio TASC, IOM-CNR, S.S. 14 km 163.5, Basovizza 34149, Trieste, Italy
| | - G Rossi
- Laboratorio TASC, IOM-CNR, S.S. 14 km 163.5, Basovizza 34149, Trieste, Italy
| | - G Panaccione
- Laboratorio TASC, IOM-CNR, S.S. 14 km 163.5, Basovizza 34149, Trieste, Italy
| | - P Torelli
- Laboratorio TASC, IOM-CNR, S.S. 14 km 163.5, Basovizza 34149, Trieste, Italy
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Rodríguez LA, Magén C, Snoeck E, Gatel C, Castán-Guerrero C, Sesé J, García LM, Herrero-Albillos J, Bartolomé J, Bartolomé F, Ibarra MR. High-resolution imaging of remanent state and magnetization reversal of superdomain structures in high-density cobalt antidot arrays. Nanotechnology 2014; 25:385703. [PMID: 25181396 DOI: 10.1088/0957-4484/25/38/385703] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/03/2023]
Abstract
Remanent state and magnetization reversal processes of a series of cobalt antidot arrays with a fixed hole diameter (d ≈ 55 nm) and an array periodicity (p) ranging between 95 and 524 nm were studied by in situ Lorentz microscopy (LM) as a function of the magnetic field. At remanence, defocused LM images showed the periodicity dependence of the magnetic states inside the lattice. A remarkable transition was observed in the type of domain structures as a function of p: for the large periodicities (p > 300 nm), conventional 90° and 180° domain walls were formed, whereas in small-period antidot arrays (p ≦ 160 nm) magnetic superdomain walls (SDWs) were nucleated to separate regions with different average magnetization direction, the so-called magnetic superdomains. In the SDW regime, a low-frequency Fourier filtering method was implemented to allow a quantitative analysis of the LM images by the transport of intensity equation method. In situ LM experiments under applied magnetic fields were performed to study the reversal magnetization process in a particular array (p = 160 nm), and clear differences were observed as a function of the magnetic field orientation. The switching process under magnetic fields parallel to the horizontal antidot rows occurs in two stages: the system first nucleates and propagates horizontal SDWs, parallel to the field. Then, at higher magnetic fields, vertical SDWs, perpendicular to the field, appear before saturation. When the magnetic field is applied at 45° with respect to the antidot rows, both horizontal and vertical SDWs are nucleated and propagated simultaneously. All the experiments were successfully correlated with micromagnetic simulations. The current study sheds new light on the magnetization reversal processes of antidot arrays and opens new possibilities of exploiting the potential of high-resolution in situ LM and new data analysis procedures to probe magnetization processes in nanomagnetism, particularly in periodic arrays of nanomagnets.
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Affiliation(s)
- L A Rodríguez
- Laboratorio de Microscopías Avanzadas (LMA), Instituto de Nanociencia de Aragón (INA), Universidad de Zaragoza, 50018 Zaragoza, Spain. Departamento de Física de la Materia Condensada, Universidad de Zaragoza, 50009 Zaragoza, Spain. Transpyrenean Associated Laboratory for Electron Microscopy (TALEM), CEMES-INA, CNRS-Universidad de Zaragoza, Toulouse, France. CEMES-CNRS 29, rue Jeanne Marvig, B.P. 94347 F-31055, Toulouse Cedex, France
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Bonilla CM, Herrero-Albillos J, Figueroa AI, Castán-Guerrero C, Bartolomé J, Calvo-Almazán I, Schmitz D, Weschke E, García LM, Bartolomé F. Parimagnetism in HoCo2 and TmCo2. J Phys Condens Matter 2014; 26:156001. [PMID: 24675016 DOI: 10.1088/0953-8984/26/15/156001] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/03/2023]
Abstract
X-ray magnetic circular dichroism (XMCD), longitudinal (χac) and transverse (TS) ac magnetic susceptibility have been measured in the RCo2 series (R = Ho, and Tm) as a function of temperature and applied magnetic field. We show that parimagnetism is a general behavior among the RCo2 ferrimagnetic series (R being a heavy rare-earth ion). XMCD results supply evidence of the presence of two compensation temperatures above Tc, defining two different parimagnetic configurations, which is a fully unexpected result. The inverse χ'ac curve exhibits a small anomaly which vanishes under low applied magnetic fields. The combination of TS and XMCD measurements allows one to depict new magnetic phase diagrams for these compounds of the RCo2 series. A new scenario allowing one to understand the observed phenomenology as a Griffiths phase-like behavior is proposed, where the amorphous RCo2 represents the undiluted system case.
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Affiliation(s)
- C M Bonilla
- Departamento de Física de la Materia Condensada and Instituto de Ciencia de Materiales de Aragón, CSIC-Universidad de Zaragoza, 50009 Zaragoza, Spain
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Farhi E, Monzat C, Arnerin R, van Vuure T, Castán-Guerrero C, Hennane C, Harraud P, Campioni G, Fuard S, Ollivier J, Willendrup P. Advanced sources and optical components for the McStas neutron scattering instrument simulation package. Journal of Neutron Research 2014. [DOI: 10.3233/jnr-130007] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Affiliation(s)
- E. Farhi
- Institut Laue Langevin, Grenoble, France
| | - C. Monzat
- Institut Laue Langevin, Grenoble, France
| | - R. Arnerin
- Institut Laue Langevin, Grenoble, France
| | | | | | - C. Hennane
- Institut Laue Langevin, Grenoble, France
| | | | - G. Campioni
- CEA Saclay SERMA/LCA, Gif-sur-Yvette cedex, France
| | - S. Fuard
- Institut Laue Langevin, Grenoble, France
| | | | - P. Willendrup
- Technical University of Denmark, Kongens Lyngby, Denmark
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Castán-Guerrero C, Sesé J, Bartolomé J, Bartolomé F, Herrero-Albillos J, Kronast F, Strichovanec P, Merazzo KJ, Vázquez M, Vavassori P, García LM. Fabrication and magnetic characterization of cobalt antidot arrays: effect of the surrounding continuous film. J Nanosci Nanotechnol 2012; 12:7437-7441. [PMID: 23035490 DOI: 10.1166/jnn.2012.6537] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/01/2023]
Abstract
We have performed an experimental study on the influence of a ferromagnetic continuous film in the magnetization reversal processes in discrete submicrometric antidot arrays fabricated on it. In order to compare the magnetic properties, two sets of antidot arrays have been fabricated over a cobalt thin film: embedded in the continuous film, and isolated by a trench surrounding the array. X-ray photoemission electron microscopy images of the virgin state show the same magnetic domain distribution in both sets of samples, finding no evidence of any effect of the surrounding film. This result is supported by the hysteresis loops measured with magneto-optical Kerr effect, as isolated and non-isolated arrays present almost coincident loops. A huge increase of the coercivity of the film is achieved, and the expected dependence on the geometrical parameters of the array is found, connecting the previous studies on the micro- and nanometric scales.
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Affiliation(s)
- C Castán-Guerrero
- Instituto de Ciencia de Materiales de Aragón (ICMA) and Departamento de Física de la Materia Condensada, Consejo Superior de Investigaciones Científicas-Universidad de Zaragoza, C/Pedro Cerbuna 12, 50009 Zaragoza, Spain
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